OSB board: what is it - a story about a universal building material

Oriented strand board (OSB) is a sheet material that is now widely used in construction. The material came from abroad, the original name was oriented strand board (OSB), so the domestic name is a translation of the foreign one. Sometimes you can find the abbreviation OSB. This is nothing more than a transliteration from English. However, it is not enough to know how the term OSB board stands for, what it is, in what areas it is used - we will look at it in this article.

OSB stack Source osbtambov.ru

The best answer to the question OSB: what is it - in the decoding of the abbreviation. The term “chip” in the name of the material means that the raw materials for production are wood particles, “oriented” means that wood chips are not laid chaotically, but in a certain way, and “slab” means the shape of the resulting material. OSB is a layered material. In the outer layers, the chips are located in the longitudinal direction, and in the inner layers - in the transverse direction.

When talking about what OSB board is and where it is used, it is necessary to consider the history of the appearance of the boards. The material appeared on the market at the end of the 20th century. It owes its appearance to the extensive construction of frame houses in America. The chipboard and plywood that existed at that time were not suitable for cladding the frame due to their heavy weight, intolerance to moisture, and poor retention of fasteners. Covering the frame with ordinary wood was expensive and low-tech. The solution was the emergence of OSB, which allows you to quickly sheathe a house frame

Frame houses are sheathed with OSB boards Source frame houses.site

Description of OSB (OSB)

Painted OSB.
In the original, the name of this product sounds like oriented strand board (abbreviated as OSB). In Russian, they operate with an exact translation of this concept - oriented strand board.

This sheet material is made from wood chips, the layers of which are glued together using a mixture of synthetic resins, wax, and boric acid. After pressing, the panel acquires high strength, which is achieved by different orientations of the chips. Its outer layers are laid lengthwise, the inner ones - across.

Material composition

The basis for the production of OSB boards are various types of wood - both deciduous and coniferous. The raw material is cut into thin chips up to 150 mm long.

The binder in production is wax in combination with adhesives, the ingredients of which include paraffin, phenol-formaldehyde or isocyanate resins.

Boric acid plays the role of an insecticide. The wood chips are mixed with these components in stages. Then the panels are formed and pressed.

Characteristics of OSB boards

In the European Union, products are manufactured according to a single standard EN300, which contains a breakdown of the key characteristics of the material.

These include:

• strength, density, load resistance;
• flexibility;
• resistance of the front (smoother) surface to abrasion;
• high-quality adhesion to various materials;
• ease of processing;
• fire resistance.

What does OSB board look like?

OSB sheet consists of several layers of wood chips. Their number, as in plywood, increases with the thickness of the material. During the production of slabs, chips must be oriented in different ways: in the outer layers - longitudinally, in the inner layers, on the contrary, transversely. This increases the strength of the products.

Each panel has a front side intended for subsequent finishing. It is smooth and looks neater.

OSB board appearance.

Performance properties

Today, 4 types of OSB boards are produced. They differ in their technical characteristics and, accordingly, have different operational properties.

Each category has its own area of ​​use where the product will perform best:

1. OSB 1 - boards of the lowest strength. They do not tolerate high humidity well and are not intended for use in construction. Their scope of application is the production of furniture or containers.
2. OSB 2 - panels of higher density. They are used for interior decoration of low-level rooms. Products with this marking are not intended for outdoor use.
3. OSB 3 - boards for outdoor work. They are resistant to mechanical stress, retain their properties in conditions of high humidity, but can become deformed when placed in water. For additional protection, the material is coated with paint, primed, and treated with special impregnations.
4. OSB 4 - panels of maximum strength. They are used for external work when installing loaded structures (floors, roofs). The material is resistant to moisture, vibration, and mechanical stress. The low distribution of slabs of this type is due to their high price.

Types of slabs.

Types of material

In addition to technical characteristics, OSB sheets may differ from each other in physical and even aesthetic properties. The appearance of the slabs and the properties of their surface determine how the material will fit into the interior and how convenient its subsequent processing will be.

Types of sheets:

1. Unpolished. The simplest option is without surface treatment - they remain rough and rough, with splinters sticking out. The advantage of unsanded panels is their low cost, good connection with other materials, and no slipping. Untreated slabs are used mainly in roofing work and when installing sheathing.
2. Polished. Here the surface of each sheet is carefully processed and cleaned. It can be coated with paint and varnish material without additional treatment. However, the cost of the material increases in comparison with the unpolished version.
3. Lacquered. These products are sanded and varnished in an industrial environment. Due to processing, they acquire additional moisture resistance and an attractive appearance.
4. Laminated. Their surface is covered with a special polymer material, which increases the strength of the sheet and its service life. Laminated products look good, but their cost is high.

Varnished OSB board.

Classification by edge

OSB boards are available with straight or profiled edges. In the first case, the mounted panels are a rough base that requires further finishing. They can be used to make containers, furniture blanks, and cut products with complex geometries.

The profiled edge allows you to obtain a finished surface without gaps or cracks immediately after installation. For this purpose, the end of the sheet has a tongue-and-groove connection or a selected quarter to ensure high-quality and even joining of products while maintaining maximum heat and moisture insulation.

Composition and production

OSB panels are made by heat pressing layer-by-layer oriented chips or small chips. This happens with the help of special equipment.

Wood (aspen, pine, spruce, poplar) is used as raw material, the content of which in the finished product reaches 90-95%. The rest is glue. The main components are wax, paraffin, boric acid, synthetic resins:

• urea-formaldehyde (OSB-1),
• melamine-formaldehyde (OSB-2),
• phenol-formaldehyde (for OSB types 3 and 4).

The production process occurs in several stages:

• Sorting of raw materials.
• Making chips. The prepared logs are sent to a planing unit, where they are split into chips.
• Drying wood chips.
• Mixing it with the adhesive base.
• Forming, rolling.
• Pressing at a temperature of 170-200 degrees.

Scope of application of OSB

The possibilities for construction use of a material depend on its class and characteristics. OSB boards 9 and 12 mm are suitable for cladding the walls of a house or installing a soft roof. For flooring, you need to buy material of greater thickness - from 16 to 20 mm.

The higher the load on the mounted structure, the more massive OSB panels are needed.

Thus, in the United States and Canada, sheets up to 32 mm are produced. They are used for installing floors in industrial premises and workshops.

Material on the topic: Classification and applications of decking boards

Laying the floor with OSV-slab.

Purpose of OSB boards

OSB boards, due to their characteristics, allow them to be used not only as a building material, but also as a finishing material. The scope of application of these plates is very extensive:

• With their help, you can sheathe the frame of a building, both inside and outside.

• The slabs are suitable for leveling both floors and ceilings.
• With their help, the finished or subfloor is laid along the joists.
• They allow you to mount split formwork when working with concrete.
• Installation of continuous sheathing when using roofing materials such as bitumen shingles, metal tiles, soft slate and other roofing materials.
• Based on them, the production of SIP panels, as well as thermal panels, has been established.

There is constant debate among potential consumers regarding the safety of OSB boards, since the binder contains formaldehyde. Manufacturers claim that only 1 percent of this substance is released, which is considered absolutely safe. Natural wood contains approximately the same amount of formaldehyde. Such materials can be used in the production of children's furniture. Recently, OSB boards have appeared that emit half as many harmful components. To identify these plates, you need to carefully look at what is written on them. Environmentally friendly products are labeled with the prefix “Bio” or “Green”, and they are much more expensive.

OSB board has a wide range of applications

Each batch of such building materials must be tested for actual formaldehyde emissions, which must be indicated in the accompanying documents. Despite manufacturers' claims, many doubt that OSB boards are environmentally friendly. Recently, there has been a general tendency to use building materials based on natural ingredients, although such materials are unaffordable for many. If the family budget allows, then people always give preference to natural building materials.

Size range of slabs

The strength of the OSB board is important to the consumer. Restrictions on the use of products in loaded structures depend on this characteristic. For the construction of walls, OSB 9 mm thick is traditionally used.

If required, you can buy sheets up to 26 mm. The length and width of the products do not change: standard size slabs are available on the Russian market: 2500 by 1250 mm.

Materials coming from North America have different dimensions. Here, the typical dimensions of the OSB panel are slightly different and are 2440 by 1220 mm. However, products from North American manufacturers rarely reach Russia.

Other OSB features

In fact, all types of OSB are becoming increasingly popular. Therefore, the scope of their application is not limited only to finishing or construction activities. Several alternative uses:

• Manufacturing of interior items. In particular – furniture. For the most part, these are frames for sofas and armchairs. Although options for cabinet products are appearing.
• Various types of containers. This may be packaging for transportation.
• Vehicle finishing. Most often truck trailers.

A material such as OSB is the key to successful construction. But many people mistakenly believe that it becomes possible not to comply with the rules and technology. OSP makes the process easier, but does not make it less responsible.

Pros and cons of the material

The strength of oriented strand board is 2.5 times higher than that of particleboard made from fine sawdust. The resistance of panels to mechanical stress of pressed panels is the same as that of softwood plywood.

The swelling coefficient of the material is about 10%. The slab can spend a day in water without losing its strength.

When making OSB boards, the chips are laid so tightly that there are no voids inside the panels. The surface is 25% better able to hold screwed fasteners than plywood or chipboard. The sheets do not delaminate because binder resins are used in their production.

The panels can withstand heavy loads. They are used when arranging floors and installing critical structures that will subsequently experience increased pressure.

Sheets maintain integrity under various types of impact, including stretching or fracture. The elasticity of the material allows it to cover curved structures.

Oriented strand board has a low mass. With a thickness of 9 mm, a standard OSB 3 product will weigh 18.3 kg, an 18 mm panel will weigh 36.6 kg.

The material is not susceptible to damage by insects and is not a medium for the development of fungus or mold.

Characteristics of WWS slabs.

Some characteristics of OSB in comparison with chipboard are shown in the table.

Characteristic	OSB	Chipboard
Ultimate strength at static bending, MPa	At least 22	From 14
Modulus of elasticity at static bending, MPa	Not less than 3500	From 1800
Swelling in water over 24 hours by thickness, %	15	Up to 30

Although there are many advantages, the material is not without some disadvantages.

These include:

• an unpleasant odor that disappears within a few days;
• evaporation of formaldehyde, which limits the use of untreated OSB sheets indoors intended for permanent residence;
• low vapor permeability, implying ventilation.

Standard sizes of OSB sheets

The width and length of OSB particle board are standardized, which is associated both with production features and with the ease of use of the material. The thickness of the OSB sheet depends on the required strength characteristics of the boards and varies among different manufacturers. The most popular sizes are presented in table form.

The most popular sheets are 1220x2440x10 mm in size; elongated sheets 1220x3660 mm with a thickness of 6...38 mm are less commonly used. Weight of OSB size 1220x2440 mm with a specific weight of 650 kg/s.cub. is:

The data is indicative as the specific gravity of the material may vary. This information should be confirmed with the manufacturer.

Since sheets (for large volume purchases) are supplied in bundles, it is often important to know the weight of the bundle and the number of sheets in it. For OSB 1, OSB 2, OSB 3 boards the data is presented in the table.

Material marking is carried out in accordance with the regulations of the country of origin.

The labeling must indicate the basic parameters of the material: sheet dimensions, type, potential conditions of use, name of the manufacturing company, production standard.

An example of marking for Canadian OSB boards, the use of which is justified for the most critical work due to high quality and cost.

1. Panel type.
2. Span length (maximum allowable distance between sheet supports) in inches.
3. Type of connection (T&G - tongue and groove).
4. Type of bonding (determined by the water resistance of the resins).
5. Production standard.
6. Sheet thickness in inches.
7. Manufacturer's plant number (enterprise code).
8. APA (Manufacturers Association) standard.
9. Availability of source materials in HUD (material use bulletin UM-40)
10. Stove type (according to Canadian standards).
11. Acceptable scope.
12. Canadian standard markings.
13. The location of the main axis of the panel.

Danger of use in residential construction

The production technology of OSB boards involves the addition of binders with a pronounced odor. It does not erode for a long time. When covering walls, installing floors or ceilings, you should take into account that the smell will remain in the room for several weeks.

If you purchased material from a trusted manufacturer, it will disappear faster. If slabs of dubious quality were purchased, the smell may remain in the house for several months.

The problem described above may arise due to the selection of the wrong category of OSB panels. Products intended for outdoor use contain resins with a different chemical composition compared to boards used for work inside residential spaces.

The danger comes from formaldehyde fumes. All sheet building materials resulting from wood processing have this disadvantage. OSB panels contain less formaldehyde than particle boards.

When choosing products for indoor use, you must ask the seller for a certificate of conformity - it confirms the safety of the products. Certified products contain small amounts of formaldehyde and other resins that are toxic to humans.

Furniture made from OSB.

Comparison with other building materials

When choosing the optimal material for construction, absolutely all the pros and cons are taken into account. Let's compare all the factors in the summary table using the following rating scale:

• “+” — low level;
• “++” — average;
• "+++" - high.

Comparison factors	OSP board	board	plywood	Chipboard	drywall
moisture resistance (without additional treatment)	++	++	+	+	+
environmental friendliness	++	+++	++	+	+++
strength	+++	++	+++	+	++
hardness	+	++	+++	+	+++
thermal insulation	+++	++	+	++	+
soundproofing	+++	++	+	++	+
vapor permeability	+	+++	++	+	+
fire resistance (without additional treatment)	+	+	+	+	+++
light weight	+++	+	++	+	+++
application for building construction	+++	++	+	+	+
life time	++	++	+	+	+++

Reliable OSB manufacturers

There are many manufacturers of slabs today. The leading positions among them are traditionally occupied by companies from Europe and North America. Russian brands are also beginning to gain popularity among builders who use OSB in the construction of houses and finishing of premises.

The slabs produced must comply with the requirements of the international standard EN 300, regardless of where they were manufactured.

Ultralam

This Russian company produces OSB boards according to additional internal standards. They reduce the amount of formaldehyde used in the production of the material. Therefore, Ultralam products are the safest option for indoor use.

The high density of the plates from this manufacturer guarantees high-quality installation of fasteners.

The self-tapping screw into the Ultralam sheet is difficult to screw into place, but during further use it will not wobble or fall out of the wall.

Ultralam is a Russian slab production company.

Kronospan

An international manufacturer whose factories are located in Latvia, Romania, Belarus, and Russia. The brand's products are distinguished by high environmental performance. OSB boards of this brand belong to class E1. They can be used for both external and internal work.

An advantage for builders is that Kronospan products have two types of surfaces: smooth front and rough internal. This significantly increases the speed of work due to the error-free positioning of the material.

Plates from Kronospan.

Glunz

Construction products made in Germany are considered high quality by default. The Glunz brand is the largest manufacturer of OSB boards in Europe.

A specialized scientific laboratory has been created on the basis of the enterprise. Its task is to improve the quality of manufactured products.

The products of this manufacturer are distinguished by a high class of fire and environmental safety, strength and durability. But its price is also higher than for analogues of other brands.

OSB from the best German company Glunz.

DOK "Kalevala"

Russia, covered with forests, for a long time could not launch its own line for the production of oriented strand board and imported goods from the EU or Canada.

The pioneer of the industry was the Kalevala brand, which uses Karelian wood chips to create OSB panels. The products are characterized by a rough surface inside and outside.

The products of this brand comply with the international standard EN300. This allows the company to sell OSB boards outside of Russia.

OSB from Russian.

EGGER

OSB sheets began to be used as a building material in Europe back in the 1960s. It's hard to guess from photos of many European houses that they are built from oriented strand boards, but it's true.

One of the first to launch the production of this material was the Austrian brand EGGER, whose history began with a small family factory.

Today it has turned into a large concern that unites about 20 factories in different EU countries and does not know what a compromise is. The brand produces OSB of only the highest quality.

OSB sheets from the Austrian company EGGER.

Varieties of oriented strand boards

Features of the production cycle make it possible to produce products with different physical and mechanical properties . OSB boards are classified into 4 groups:

• OSB-1 – panels are designed for non-load-bearing structures and operation at low humidity.
• OSB-2 - sheets have high mechanical strength and can serve as the basis for load-bearing structures. Used in dry rooms.
• OSB-3 - strength characteristics allow the manufacture of load-bearing structures and their operation in conditions of high humidity.
• OSB-4 is a moisture-resistant and durable material used for loaded structures. It has excellent performance, but its application is limited by its high cost.

OSB 3 grade is used more often than other types in construction work. Its popularity is explained by its increased resistance to moisture and stress at an affordable cost. OSB boards measuring 1250x2500 mm are suitable for cladding external and internal walls, creating continuous sheathing, constructing temporary structures and fencing.

According to the degree of surface treatment, the sheets are:

• Unsanded – the products are rough, they are recommended as a base for roofing and serve as a base for a bitumen primer.
• Sanded - the surface is machined and becomes smooth. The material is used as flooring.
• Varnished - one side is primed and coated with clear varnish.
• Laminated - paper impregnated with resins is applied to the outer layer, the coating is fixed by hot pressing. Purpose – installation of reusable formwork.

Unsanded

Sanded

Varnished

Laminated

The edges of the products can be smooth or the ends are processed for a tongue-and-groove connection.

Painting and finishing of slabs

Panels with a smooth polished surface are ready for finishing immediately after installation.

Any compositions intended for woodwork are suitable for painting:

• acrylic paints - are considered environmentally friendly, dry quickly, protect the construction material from moisture, creating a thin protective film on it;
• polyurethane - more suitable for painting external walls;
• latex - non-toxic, they can be used to paint surfaces inside the house;
• oil-based ones will help protect the ends of the slabs, but they take a long time to dry and have an unpleasant odor.

OSB sheets are also suitable for wallpapering. The surface does not have to be plastered - just sand it and seal the joints between the panels with acrylic or silicone sealant.

The technology for installing OSB panels provides for the presence of a damper gap that compensates for temperature deformations of the material. If the cracks are left unsealed, the wallpaper will form folds or tear at the joints of the sheets.

The surface ready for gluing is primed. It is better to choose a dense covering for the walls, then the wood structure of the slabs will not show through the canvas. A good solution would be vinyl wallpaper on a non-woven or paper backing.

To plaster a facade made of OSB panels, it is necessary to choose elastic plasters or use the “layer cake” technology, where the lower membrane layer protects the surface from cracking at the joints of the slabs.

Processing OSB boards for gluing.

Finishing methods

OSB boards that have become partitions, walls, floors or ceilings of residential or non-residential premises can be decorated using a variety of methods. Although some homeowners purchase products with a varnish coating and do not use additional finishing methods.

• Painting. This way you can decorate both interior rooms and exterior walls. Procedure: if the material is not sanded, then it must be pre-treated with a sanding machine;
• prime the surfaces with a product specifically designed for wood boards. Otherwise, the primer simply will not “stick”;
• then you need to sand it again; The final stage is applying paint. You can use oil, acrylic, polyurethane, latex compounds.

• Laying ceramic tiles. This option is only suitable for interior decoration. In this case, special attention should be paid to the glue; it must be intended for OSB.

• Finishing with artificial brick (stone). This way you can create decor both inside and outside the house.

• Wallpaper sticker. This option turns out to be excessively expensive, because you will first have to apply a primer to the OSB sheets (it is better to do 2 layers), then cover them with interior paint and only after that stick the wallpaper. Or, as a base, first cover the walls with plasterboard, and then stick them.

• Covering the exterior walls of a building with siding. Obviously, this method is not suitable for interior work.

• Creation of an exterior in half-timbered style. First, paint is applied to the walls (with preliminary priming), then they are “embroidered” with wooden elements in strict adherence to the geometric pattern.

Cost of OSB boards

The price of the panels will be determined by their thickness, dimensions, category, and manufacturing company. On the Moscow market, the cost of a typical 9 mm OSB sheet size is about 650 rubles.

For loaded structures, it is advisable to purchase 18 mm products for 1200 rubles. The product was produced by a Russian company. If you wish, you can find OSB from the German brand EGGER: prices for a standard product with a thickness of 12 mm start from 1000 rubles.

Buying OSB 4 is more difficult than class 3 material: 12 mm Kronospan products are offered for 900 rubles, but this material will be delivered if the order is fully paid.

Installation features

When installing slabs, it is important to follow the rules. The panels are attached to the wall through the sheathing with self-tapping screws, the length of which should not be less than 25-45 mm. They are screwed in at a distance of 10-15 cm from each other. They must be at least 1 cm from the edge of the sheet.

The plates do not fit tightly together; gaps of 2-3 mm are made between them. They help prevent the slabs from deforming due to their expansion as a result of changes in the level of moisture in the room.

OSB can be installed in another way directly on the walls. To do this, drill holes in the slabs, put them in place, make holes in the wall, insert dowels and screw in self-tapping screws. If they are attached to a wood base, then they are secured with hardware without first using a hammer drill.

OSB grade (according to American classification)

OSB panels, which are produced by North American companies, end up in Russian retail outlets with their own specific markings, since they do not pass the European certification familiar to our compatriots. Therefore, due to user errors, there are so many cases of American OSB being used for other purposes – with corresponding results.

Manufacturers in the USA and Canada, when testing products and classifying OSB, rely on a couple of “their” standards:

• CSA O325 Construction Cladding.
• PS 2 “Quality standard for wood-based building panels”.

The plate will necessarily indicate by what standard the tests were carried out. By the way, manufacturers often use both standards to test products, which is indicated during labeling. There is no problem with this, since the requirements of these documents are identical in most important provisions. Here, the overall load-bearing properties, resistance to loads in dry and wet conditions, the level of water absorption, swelling, and so on are assessed.

North American firms simplify the task of choosing as much as possible. Instead of classes indicating the specific properties of the sheet material, they are required to print (in letters and numbers) on the panel a mark indicating the PURPOSE. The user can only buy OSB of the appropriate brand and select the required standard thickness of the slab.

You can find the following list of brands (CSA O325):

• W – OSB for wall cladding
• 1F – slabs for creating flooring
• 2F – slabs for creating horizontal flooring on top of some continuous rough layer
• 1R – panels for creating a continuous roof sheathing (without creating support at the edges)
• 2R – panels for creating a continuous roof sheathing (with support at the edges)

Obviously, OSB is a fairly universal material, so the same model often belongs to several brands, which is why you can find this type of designation: 2F16/W24/1R24

You can be sure that a slab with the above markings is suitable for: roofs, walls and floors. You probably noticed the numbers 16 and 24 after the brand. This is not the thickness, these are the maximum permissible SPANE SIZES. That is, the manufacturer calculated for us and indicated (in inches) what the distance between the load-bearing elements of the frame should be. Moreover, on slabs that are used as a structural (not decorative) material, markings are often applied in the form of lines indicating where the racks will be and where to install the fasteners.

Marking of OSB boards in the USA

According to the PS 2 standard, MAXIMUM SPANS are also indicated for the installation of OSB boards. The presence of “double” numbers with a line (such as 20/16) indicates that the panel can be installed on a roof where the distance between the rafters (or counter-lattice bars) should be no more than 20 inches. If the first number indicates the size of the spans for roofing slopes, then the second indicates the optimal spans if OSB is used for cladding the frame floor.

In order to understand which American OSB can be used outdoors and in wet rooms, and which cannot, you should know about the characteristics of the binder used. Look for the inscriptions “Esposure Type Binder”, “Exterior Bond”, “Interior” in the labeling. The first two types of boards are suitable for creating structures in wet conditions (in terms of moisture resistance they approximately correspond to the European brands OSB-4 and OSB-3). It makes sense to buy the “Interior” type of OSB only for “Interior”, that is, for indoor use. This is the equivalent of OSB-2 and OSB-1.